In general, a workpiece may be attached to a spindle of a machine tool, rotatably mounted in a housing for stock, e.g. the head stock of a lathe, by affixing a chuck, face plate or collet to the spindle and clamping the workpiece between the jaws of the chuck, within the releasing structure of the collet or onto the plate or a pallet or workpiece carrier which can be so engaged or can be substituted for the face plate.
Rapid removal and replacement of the workpiece is important since much time can be lost if each workpiece must be unclamped and a new workpiece clamped in place on the machine directly.
Accordingly, it is desirable to provide the machine with a quick-change capacity for a workpiece.
German open application DE-OS No. 35 28 443, for example, describes a coupling for the releasable attachment of a workpiece carrier to a machine tool utilizing a number of clamps and within a receptable into which the workpiece carrier can fit. The clamps are located around the receptacle for the workpiece carrier and about the axis along a circle and have hook-like members movable radially with respect to the axis.
The clamps engage in an annular groove of the workpiece carrier in the coupling position and lock the workpiece carrier in place while a planar array of teeth or serrations, such as a Hirth crown of teeth on the carrier and the receptacle and lock into engagement to transfer torque between the workpiece and the receptacle.
The actuation of the clamps is effected by a complex system of shifting rods and pivotal levers through an actuating system which traverses the main spindle so that the passage normally provided in the main spindle is obstructed and cannot be used for other purposes.